The United Nations is flying humanitarian aid from Iraq to northern Syria, where people already affected by more than two and a half years of fighting are dealing with harsh winter conditions.

The aid flights began Sunday and are due to continue for 10 days, bringing in tons of food, blankets and health supplies.

Syrian Refugees by Country

Lebanon: 909,639

Jordan: 596,800

Turkey: 594,854

Iraq: 217,144

Egypt: 133,267

Source: UNHCR

The U.N. refugee agency said the aid is intended to help 60,000 Syrians who have been forced from their homes. The fighting has restricted access to parts of Syria, and the agency says no "significant deliveries" of aid have reached Al Hassakeh province, where many refugees are located, since May.

The airlift was delayed from last week because of winter storms sweeping the region. The governments of Syria and Iraq approved the flights.

The U.N. has reported that Syria's civil war has forced more than 2.2 million refugees to flee the country and 6.5 million others to leave their homes inside of Syria. That represents nearly 40 percent of the country's population.

In some of the latest fighting, a Britain-based activist group, the Syrian Observatory for Human Rights, says government air strikes Sunday killed at least 36 people, including 15 children, in the northern city of Aleppo.

Activists said helicopters dropped barrels laden with explosives on residential neighborhoods in the worst raids against the city in six months.

The Observatory also reported at least 28 people had been killed in Adra, northeast of Damascus, since an al-Qaida-linked rebel faction attacked there on Wednesday.